Various techniques are known in the art for applying panels to cover a deck or to function as a siding of a wall. Slate is a particularly desirable type of panel. It is difficult to mount slate on a deck by virtue of the slate being a natural product, lacking true uniformity in dimensions, being brittle and having varying hardness characteristics. Conventional mounting is done by nailing the individual slate panels to a deck through preformed holes. The procedure has not changed essentially for centuries. An alternative procedure is to use hooks that are attached directly to the deck and engage the edges of the slate. There are significant drawbacks to the hook system, and also to the nailing procedure which requires much skilled labor and involves breakage.